Vaillant COMBlcompact VCW 242E User manual

Vaillant Training/Logical Fault Finding Guide for all
COMBlcompact and THERMOcompact models
v
t
v
~Vaillant
HEATING,CONTROLS,HOTWATER.

;"
tWJVaillanl
HEATING,CONTROLS,HOTWATER.
Contents
~~
Guidance Notes
IICD
l' ."...
V
If
Room Sealed Fan Flued Models (RSF)
COMBlcompact
VCW 242E, 282E
THERMOcompact
VC112E, 142E, 182E,242E, 282E Ii)
)r:-'
.
'-:14
.
Balanced Flue & Open Flue Models
COMBlcompact
VCW221, 240, 280
THERMOcompact
VC110, 180, 240, 221.

t¥JVaillant
HEATING,CONTROLS,HOTWATER. [!]
Guidance Notes (should be read before using this fault finding guide)
1. Check you are using correct guide for your appliance.
See index and check model number.
2.Always start at the beginning of guide and work
through one step at a time.
3.AII guides deal with central heating (C/htg) first, then
hot water (D.HW.)
Do the same when following guides.
4. When checking 240v AC mains voltage use terminal 1
on appliance terminal strip as the neutral test point.
~5. When checking D.C. voltage use terminal 9 on
appliance terminal strip as the negative test point.
(All D.C. voltages are low voltage).
10
5
6
1
Q
7
Note 1 It is law* that any work carried out on a gas
appliance must be carried out by a competent person
who is registered with CORGI (Council for Registered
Gas Installers).
Note 2 All work involving electricity must be carried
out by a competent person who is responsible for
electrical safety checks.
*Gas Safety (Installations and Use) Regulations 1984
Gas Safety (Installations and Use) Amendment
Regulation 1990
6.ln order to use this fault finding guide ensure that the
operating mode of circulating pump is set to operating
mode (I) (selector plug adjacent to appliance terminal
strip makes electrical connection to contact one) see
diagram.
TIISI
0Gro GroG
7. Note that illustrations and pictures are shown only
once and are not duplicated again in this guide.
Each illustration/picture has been given a reference
number.
9
3
FRONT CONTROL PANEL
Key
1. Yellow neon indicating power to operator.
2. Green neon indicating operation of Diaphragm pump.
As voltage decreases to diaphragm pump so neon loses
luminosity.
3. 0.16 amp anti surge fuse.
4. Time delay adjustment (factory set 5 minutes,
adjustable 1-12 minutes).
5. Fault suppression button (ignition lockout).
6. Indicating neon (lockout).
7. 2 x 2 amp fuses (L&N).
8. Variable potentiometer controlling central heating flow
temperature only.
9. Red neon rocker switch for power on.
10. Central heating rocker switch (not fitted on VC
appliances) .
4
2
8

t¥JVaillanl
HEATING,CONTROLS,HOTWATER.
Room Sealed Fan Flued Models (RSF)
guidance note 6)
Q.
11
+
YES
+
1

:g
~....
f...l
~
~
YES
~
Cr
...
I
~Vaillant
HEATING,CONTROLS,HOTWATER.
[!]
(c) Check appliance not in time
delay (isolate power, wait 5
seconds and restore).
(d) Check anti surge fuse
(0.16 amp).
...

~
$J
Inoe. pU\pPrun1
t
YES
,
[Go ill 4
~
Check hydraulic operation OK ?
1. Hydraulic diverter valve
moves leftcloses microswitch
M2 (VCWonly)
T
~
2. Differential valve opens.
TPic14
[Goto 5
4
I',
tiJVaillanl
HEATING, CONTROLS,HOTWATER.
~NO" (a) Check 240vACacross
pump terminals
TPic10
(b) Check pump free to rotate
and not stuck
TPic11
~.
Itv
If(a) and (b) are OK.- change
pump.
I~NO
(a) Check appliance and
system full, pressurised and
vented of air.
(b) Check servo valve is in
C/htg position, return spring
holds carn down (VCW
only).
T
(c) Check for dirt, sludge,
flux or inhibitorcausTng
frothing in system
affecting:-
1. Pump performance
2. Hydraulic diverter valve
(VCW only)
3. Servo valve (VCW only)
4. Connecting tubes
5. Main heat exchanger
6. Differential valve
Pic12
M3
OPEN G
Rear view
I

~
Does applianC1
ignition?
T
~
(yellow neon glowing front
control box)
0
YES
~
~Vaillant
HEATING,CONTROLS,HOTWATER. ~
I~O~ (a) Check microswitchM2
(20v DC)is makingcontact
and closed circuit(VCW
only).
T
(d) Checkcombustion
chamber seals.
(e) Cneck air
switcn"tubes
kinkedand Sl
., top cover plate clear.
T
Pic15
(b) Check fan pressure
switch oper9tes (240v AC
:fromboth sides of switch to
neutral terminal 1) ifnot
check C to F
TPic16
(c) Check flue installation:
-Joints correctly located
- Flue not blocke(
- Terminal position
(1)Check fan working
correctly.
Ifall above OK change fan
pressure switch.

~
@J
Does burner light and
remain alight?
~
YES
~]
~Vaillant
HEATING,CONTROLS,HOTWATER.
~NO~ N;B. For lockoat (Black
button & Red Neon)
problems when no flame is
visible check A to F.
T
t
\)~rnenflame is visible prior
to lockout checkFto H only
(a). Check gas supply to
appliance live and purged.
(b). Check differential valve
open (if no return to Q4).
(c). Check20v DC across
gas operator, if available
but operator fails to open
(audible click) change
operator.
T
t
(d). Check central heating'
overheat thermostat and
connection (should be
closed circuit, if open
change component).
T b " Pic22

71
I
~
~
YES
~
Goto 8
~fjJ
YES
~Vaillant
HEATING,CONTROLS,HOTWATER.
I~O~ (a) Check standing and
working gas pressure at
appliance inlet.
TPic25
~
(c) Check voltage across
diaphragm pump (approx 6v
DC) withNTC disconnected.
TPic27
J
(b) Check diaphragm pump
operating tubes and throttle
jet clear.
TPic26
NO~ (a) TestNTC/Elebtronic
board.
Pull off NTC wire (from
D.H.W. overheat) touch it
on chassis, if burner goes
off, change NTC.
TPic29
(d) Check burner pressure
settings low and high fire rate.
TPic28
(e) Check and/or replace gas
operator.
If burner stays on change
electronic board.
(The gas operator may be
stuck open eg debris. This
symptom is very unlikely
but can be checked by
pulling offthe wire to
operator. Ifburner remains
alight then change
operator).

~Vaillant
HEATING,CONTROLS,HOTWATER.
@
(a) Check demand for hot
water-tap open and supply
pipes correct way round.
(b) Check water section
moves servo valve cam - if
not check venturi/diaphragm
of water section.
..
~o~
~
YES
!
Pic 30
(c) Check microswitCh M3
(20v DC) is making contact
and closed circuit.
.. Pic31
(d) Check hy
valve moves
microswitch r
open no eTec
through switch).
..
M3
CLOSED ~
(e) If D
check gas -
pressure at
& burner pr'
Pic 25 & Pic 28.
(1) If water fl<
insufficientc 0
adequate cold water mainO,
supply and/or blockage in
water section or DHW
~